Projectile fuze with flexible baffle

ABSTRACT

The nose cavity of a projectile fuze is provided with a flexible, discontinuous baffle, in the form of a spiral coil spring, mounted between the firing pin and the front end of the fuze, for dissipating the kinetic energy of light objects, such as rain drops or foliage. The open front end of the nose cavity is closed by a thin dust cover which is easily penetrated by light objects.

9 a g Emilee Etates Eetent 1 1 1111 3,54,4e2 Kosonoclsy Dec. 17, 1974 [54] PROJECTILE FUZE WITH FLEXIBLE 2,779,285 1/1957 Kuller 102/73 R RAFFLE 3,l35,206 6/1964 Hjelm et al. l02/73 R 3,726,228 4/1973 Lohninger 102/73 R [75] Inventor: Stephan Kosonocky, Whippany, NJ.

[73] Assignee: The United States of America as represented by the Secretary of the Army, Washington, DC.

[22] Filed: July 30, 1973 [21] App]. No.: 383,646

[52] US. Cl 102/73 R [51] Int. Cl. F42c 1/00 [58] Field of Search 102/70, 73, 76

[56] References Cited UNITED STATES PATENTS 1,666,792 4/1928 Remondy 102/73 R Primary Examiner-Samuel W. Engle Attorney, Agent, or FirmEdward J. Kelly; Herbert Berl; Thomas R. Webb [5 7] ABSTRACT The nose cavity of a projectile fuze is provided with a flexible, discontinuous baffle, in the form of a spiral coil spring, mounted between the firing pin and the front end of the fuze, for dissipating the kinetic energy of light objects, such as rain drops or foliage. The open front end of the nose cavity is closed by a thin dust cover which is easily penetrated by light objects.

5 Claims, 2 Drawing Figures PROJECTILE FUZE WITH FLEXIBLE RAFFLE BACKGROUND OF THE INVENTION Artillery projectile fuzes are usually made very sensitive to target impact for maximum effectiveness. This sensitivity, however, makes the fuze susceptible to undesired in-flight functioning when rain drops, foliage, or other discrete light objects are encountered. Therefore, artillery fuzes have been desensitized to prevent such undesired functioning by providing the nose with baffles such as thin plates, cross-bars or cruciform inserts for dissipating the kinetic energy of such light objects. However, such baffles, being rigid, produce an undesirable reduction in the sensitivity of the fuze to the normal massive targets for the projectile.

SUMMARY OF THE INVENTION An object of the present invention is to provide a projectile fuze with an improved baffle for preventing undesired functioning of the fuze by discrete light objects, such as rain drops, foliage, etc.

A further object is to provide such a baffle that will present a minimum of resistance to continuous target media, such as water, sand, rock and metals.

These and other objects are achieved by mounting, in the nose cavity of the fuse, and between the firing pin and the front end of the fuze, a flexible discontinuous baffle, designed to resiliently absorb at least the major portion of the kinetic energy of light objects and, in the case of rain drops, to break up the drops into droplets of small mass while permitting continuous water to pass freely therethrough. Preferably, the baffle is in the form of a spiral coil spring which varies from a small diameter in the middle to a large diameter at each end. The open end of the nose cavity may be closed by a thin dust cover which is easily penetrated by light objects.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I in the annexed drawing is a side view, partly in axial cross-section, of an artillery projectile fuze embodying the present invention.

FIG. 2 is a similar view of a modification.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. I, the numeral 1 indicates an impact fuze for detonating the explosive charge carried by an artillery projectile 2, a portion of which is shown in dashed lines. The fuze 1 comprises a conical body 3 having a threaded base stub 4 for attaching the fuze to the projectile. The fuze body 3 may contain additional components for safing, arming and other fuze functions.

The fuze body 3 is formed with an axial cylindrical nose cavity or recess 5 comprising an inner portion 7 and an outer portion 9. A firing pin 11 has a head 13 slidably disposed in the inner cavity portion 7 and an integral shaft 15 disposed in an axial bore 17 and adapted when actuated to initiate a conventional stab type primer or cap (not shown) or initiating the detonation of the main explosive charge (not shown) of the projectile 2. The firing pin is held away from its firing position (upwardly in the drawing) by a crush cup 19 interposed between the head 13 and the base of recess portion 7.

In accordance with the present invention, an improved baffle assembly 23 for dissipating kinetic energy of discrete, light objects, such as rain drops and leaves, is interposed between the firing pin head 13 and the outer or front end of the nose cavity 5. Baffle assembly 23 comprises a spiral coil spring 25, preferably of stainless steel wire, coaxially supported in the outer portion 9 of nose cavity 5 by means of a retaining sleeve 27 seated in portion 9 and two retaining rings 29 at each end of sleeve 27 with the ends of coil spring 25 resiliently abutting the two rings 29. The inner ring 29 also serves as a rigid stop for the firing pin head I3, as shown in the drawing. The baffle assembly 23 is retained in the cavity portion 9 by peening over the outer end of body 3, as shown at 31. Preferably, the baffle coil spring 25 is formed with a small diameter in the middle and a large diameter at each end, as illustrated. For example, the inner diameter in the middle may be about 4 mm. As shown in the drawing, the turns of spring 25 are close-spaced, with a spacing less than the inner diameter in the middle, which is the maximum spacing between adjacent parts of the spring.

The body 3 and sleeve 27 may be formed with one or more communicating holes 33 and 35, respectively, located near the base of the baffle assembly 23, to permit accumulated moisture to drain from the nose cavity 5. Also, the open end of nose cavity 5 may be closed by a thin dust cover 37 that is easily penetrated (ruptured) by light objects.

FIG. 2 illustrates a modification of FIG. 1, wherein the firing pin head has a smaller diameter, the retaining ring 29 is replaced by a flat ring 29' having a smaller diameter aperture, and the crush cup 19 is replaced by a shear type cup 19 interposed between the head 13 and the base of recess portion 9.

When the projectile with the improved baffle is fired toward a target or target area and encounters discrete light objects of small mass, such as rain drops or tree leaves, most or all of the kinetic energy of the objects is absorbed or dissipated by the improved baffle, thereby preventing undesired functioning of the fuze. Being flexible and resilient, the baffle 25 absorbs the impact of the light objects without transmitting effective actuating force to the firing pin. In the case of rain drops, the baffle 25 also breaks up the drops into droplets of small mass, and consequently, small energy.

On the other hand, when the projectile with the improved baffle encounters a continuous massive target, such as a solid or liquid surface, the baffle 25 offers little resistance to such a target. In the case of a hard solid target, such as rock or steel, the front end of the fuze will collapse and the firing pin 11 will be driven by the target into the primer, crushing or shearing the cup 19 or 19, respectively. In the case of a continuous loose target medium, such as water or sand, the medium is ingested into the nose cavity 5, through the discontinuous baffle coil 25, and impact pressure is applied thereby to the firing pin 11.

The foregoing disclosure and drawings are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense. I wish it to be understood that I do not desire to be limited to exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

What is claimed is:

I. A fuze, for an explosive projectile, comprising:

a fuze body having a rear portion adapted to be attached to the front end of a projectile and a for ward end adapted to impact a target, said forward end being formed with an enlongated axiallyextending cavity open at the front end and having a stop intermediate the ends thereof:

firing pin disposed within said body behind said stop and including a head slidable in said cavity; and

flexible resilient discontinuous baffle mounted in said cavity, said baffle comprising a spiral coil spring extending between said stop and said open end and having close-spaced turns with a maximum spacing therebetween of about 4 mm., to form a barrier to discrete light objects, such as raindrops or foliage, having minimum dimensions greater than said maximum spacing, for dissipating the kinetic energy of said light objects and preventing said light objects from passing through said baffle and actuating said firing pin.

2. A fuze as in claim 1, wherein said coil spring is formed with a small inner diameter in the middle increasing to a large diameter at each end.

3. A fuze as in claim 2, wherein said inner diameter is about 4 mm.

4. A fuze as in claim 1, wherein said stop is a ring fixed in said cavity and interposed between said firing pin head and the rear end of said coil spring.

5. A fuze as in claim 4, further comprising a retaining sleeve surrounding said coil spring and seated in said cavity, and a second ring mounted in said sleeve and engaging the front end of said coil spring. 

1. A fuze, for an explosive projectile, comprising: a fuze body having a rear portion adapted to be attached to the front end of a projectile and a forward end adapted to impact a target, said forward end being formed with an enlongated axially-extending cavity open at the front end and having a stop intermediate the ends thereof: a firing pin disposed within said body behind said stop and including a head slidable in said cavity; and a flexible resilient discontinuous baffle mounted in said cavity, said baffle comprising a spiral cOil spring extending between said stop and said open end and having close-spaced turns with a maximum spacing therebetween of about 4 mm., to form a barrier to discrete light objects, such as raindrops or foliage, having minimum dimensions greater than said maximum spacing, for dissipating the kinetic energy of said light objects and preventing said light objects from passing through said baffle and actuating said firing pin.
 2. A fuze as in claim 1, wherein said coil spring is formed with a small inner diameter in the middle increasing to a large diameter at each end.
 3. A fuze as in claim 2, wherein said inner diameter is about 4 mm.
 4. A fuze as in claim 1, wherein said stop is a ring fixed in said cavity and interposed between said firing pin head and the rear end of said coil spring.
 5. A fuze as in claim 4, further comprising a retaining sleeve surrounding said coil spring and seated in said cavity, and a second ring mounted in said sleeve and engaging the front end of said coil spring. 